This application seeks partial support for a FASEB Summer Conference on Protein Phosphatases to be held from July 23 to July 28, 2000 at Copper Mountain, Colorado. This will mark the tenth anniversary of this meeting. At the dawn of a new millennium, the success of the previous conferences and the widely recognized role of these enzymes in regulation of many cellular functions amply justify the existence of such a conference. Research on protein phosphatases is at an exciting and rapidly moving stage, revealing the fundamental importance of these enzymes in pathways that govern most aspects of cell life and death. It is now clear that phosphatases are equal partners with protein kinases and research on protein phosphatases is essential for our understanding of the control of cellular functions. Within the past few years, a large number of phosphatases and phosphatase regulatory/targeting subunits have been identified. A major focus of current research is to understand their physiological role and the multiplicity of ways they are involved in signaling. Protein phosphatases offer potential targets for development of new and specific pharmacological agents. Phosphatases have already been identified as the targets for immunosuppressant drugs, tumor promoters, DNA tumor viruses and a wide variety of natural toxins. PTEN, a member of the family of dual specificity phosphatases, has recently been identified as the product of a tumor suppressor gene. The involvement of PP2B/calcineurin in skeletal and cardiac muscle hypertrophy has become apparent and the PTP1B has been implicated in insulin action and obesity. The purpose of this conference is to bring together investigators studying various aspects of protein phosphatases and to disseminate the most recent information in the field. There is a constant infusion of new researchers from various disciplines into this area and the 2000 conference will be important for a focused presentation and discussion of the most recent advances in the genetics, biochemistry and function of protein phosphatases. The Conference will consist of eight sessions, each with at least six speakers, selected from investigators who have made important recent contributions and from submitted abstracts. This will help to ensure inclusion of young investigators, women and minorities as primary participants. In addition, two poster sessions will be organized. Overall, rapid progress is being made in the identification of the diverse functions of protein phosphatases in normal and pathological conditions, such as diabetes, cancer, neurodegenerative conditions, developmental and immunological defects and cardiovascular diseases.